I am still working days (and nights) to push my theme forward. The progress is quite amazing. IMO there is no doubt, that we should go for FrontEnd component system. This in combination with fast ajax requests can lead to a damn good result. And the good: the core needs almost no adjustments. I have only a few very simple overrides...
Here is a sneak preview of a fast customer journey:
genzo_theme-preview.webm
I work often with modals. This gives a much better user experience (especially on mobile devices). But in general it's all about the usage of predefined components: https://www.genzo.ch/tb-framework
Here you can see the module "tb_framework". As you click through the Elements/Components you will see a lot of elements, that you saw in the video. Any theme/module can use these components as well.
I won't publish my theme/components as they should be unique for my store. But I could open source the technique behind it. Especially the "tb_framework" module. Steps to get a similair result like mine:
Somebody builds default components for "tb_framework". Best would be without any framework. Actually I did mine only with TailwindCSS, which means, that it's also possible without any at all. Only exception might be slider functionality. (Ofc I could support this task with my components).
A new theme from scratch is created (or maybe existing cisero), that implements the components from "tb_framework". For the theme imo any framework can be used.
Core modules are adjusted to use components from "tb_framework" module. (This is not too hard and actually quite fun)
My opinion: As this is damn much work, I don't think we will find one guy, that makes this in his free time. A crowdfunding might be needed.